We remained for five days in the town of the Inca Atahuallpa, which at that time scarcely reckoned seven or eight thousand inhabitants. Our departure was delayed by the number of mules which were required for the conveyance of our collections, and by the necessity of making a careful choice of the guides who were to conduct us across the chain of the Andes to the entrance of the long but narrow Peruvian sandy desert (Desierto de Sechura). The passage over the Cordillera is from north-east to south-west. Immediately after quitting the plain of Caxamarca, on ascending a height of scarcely 9600 (10230 English) feet, the traveller is struck with the sight of two grotesquely shaped porphyritic summits, Aroma and Cunturcaga (a favourite haunt of the powerful vulture which we commonly call Condor; kacca in the Quichua language signifies "the rock.") These summits consisted of five, six, or seven-sided columns, 37 to 42 English feet high, and some of them jointed. The Cerro Aroma is particularly picturesque. By the distribution of its often converging series of columns placed one above another, it resembles a two-storied building, which, moreover, is surmounted by a dome or cupola of non-columnar rock. Such outbursts of porphyry and trachyte are, as I have before remarked, characteristic of the high crests of the Cordilleras, to which they impart a physiognomy quite distinct from that presented by the Swiss Alps, the Pyrenees, and the Siberian Altai.
From Cunturcaga and Aroma we descended by a zig-zag course a steep rocky declivity of 6400 English feet into the deep cleft valley of the Magdalena, the bottom of which
